[jira] [Commented] (IGNITE-5490) Implement replacement for obsolete CacheMetrics#getOffHeapAllocatedSize

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-5490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16268179#comment-16268179 ] 

ASF GitHub Bot commented on IGNITE-5490:
----------------------------------------

GitHub user sunnychanwork opened a pull request:

    https://github.com/apache/ignite/pull/3100

    IGNITE-5490 Ignite Continuous Query might not send update request

    During continuous query setup, there are potential updates in flight that would potentially have a situation like this:
    
    T1 updates E1, lsnrs!=null, obtain update counter 1
    T2 updates E2, lsnrs==null, obtain update counter 2
    T3 updates E3, lsnrs!=null, obtain update counter 3
    
    Notice that as E1 E2 and E3 are different there are no locks and they can proceed in parallel. As a result, the sequence of updates being sent to CQManager will be 1,3 with 2 missing and it will wait for update 2 forever which will never come.
    
    To fix this I propose to use a ReadWrite lock to ensure that the Map Entry update will complete before setting up new continuous query.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/sunnychanwork/ignite IGNITE-5960

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/ignite/pull/3100.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #3100
    
----
commit 3cff5cf0ebc282c9300613e4d6726df5dd56ab60
Author: Sunny Chan, CLSA <su...@clsa.com>
Date:   2017-11-28T05:52:14Z

    IGNITE-5490 use a ReadWrite lock to ensure that the Map Entry update
    will complete before setting up new continuous query

----


> Implement replacement for obsolete CacheMetrics#getOffHeapAllocatedSize
> -----------------------------------------------------------------------
>
>                 Key: IGNITE-5490
>                 URL: https://issues.apache.org/jira/browse/IGNITE-5490
>             Project: Ignite
>          Issue Type: Improvement
>          Components: cache
>    Affects Versions: 2.0
>            Reporter: Ivan Rakov
>
> With new 2.0 architecture, many caches can share one memory policy. Memory metrics allows to measure memory usage (loaded pages) for the whole policy. However, there's also a need to measure how much memory (or pages) is used by each cache.
> Before 2.0 such information was accessible with CacheMetrics#getOffHeapAllocatedSize, but current implemetation returns 0.
> We should either implement it or provide alternative metrics (e. g. approximate number of loaded pages per cache). Please note that if persistence is *disabled*, precise number of loaded pages per cache is not defined - one page can contain entries of different caches.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)